Various compression-style systems currently exist for treating heart diseases and conditions such as congestive heart disease and valvular dysfunction. These systems typically involve either: (a) jackets that are placed around the heart to limit heart expansion to treat congestive heart disease, or (b) bands that are placed around the heart with fillable chambers to exert localized pressure to re-form the shape of heart valves, for example to minimize valve leakage.
An example of the former is found in the Acorn Cardiovascular Inc. system set forth in U.S. Published Patent Application 2010/0160721 entitled “Cardiac Support Device With Differential Compliance.” This device is used to treat congestive heart disease. Congestive heart disease is the progressive enlargement of the heart. This enlargement requires the heart to perform an increasing amount of work. In time, the heart cannot supply an adequate amount of blood, resulting in a patient that is fatigued and in discomfort. The Acorn Cardiovascular Inc. system is a cardiac support device that limits heart expansion using a flexible jacket positioned around the heart. In operation, the jacket surrounds the myocardium and provides reduced expansion of the heart during diastole. The jacket has upper and lower ends. The upper end is open. The lower end may be open or closed. The jacket is sized for the particular heart to be contained within its volume. When placed on the heart, the upper end of the jacket extends up to the valvular annulus and terminates along the AV groove. The jacket itself further extends down to constrain the lower ventricular extremities. In this position, the jacket provides sufficient constraint at the valvular annulus. Alternatively, the jacket may not cover the apex of the heart (but it will cover its left and right ventricles). This placement is desirable as it presents a constraint against enlargement of the ventricular walls of the heart. After the jacket is positioned on the heart, it can then be secured to the heart, for example, by suturing at various locations around its circumference. However, it is preferred to avoid excessive suturing locations as this would restrict contraction of the heart during systole. Once placed, the jacket's volume and shape can be adjusted by gathering together and suturing excess material. Specifically, the jacket is adjusted to be snug during diastole (without being too tight such that left ventricular pressure will rise). The jacket then constrains enlargement of the heart beyond this volume.
An example of the second type of system is found in Mardil, Inc.'s U.S. Pat. No. 8,092,363 entitled “Heart Band With Fillable Chambers To Modify Heart Valve Function.” This device has a plurality of fillable chambers that exert inward radial forces on heart valves. These fillable chambers are disposed within the inner and outer layers of a silicone rubber band. In operation, this device is used to treat dilation of heart valves by applying localized pressure to the surface of the heart. For example, a pair of these fillable chambers positioned on either side of the mitral valve can be used to re-shape the mitral valve such that mitral valve leakage is minimized or stopped.
As can be seen, these two above systems operate quite differently on the patient's heart. The first (i.e.: Acorn) system stabilizes the base of the heart, but does not provide localized therapeutic pressure on the heart valves. The second (i.e. Mardil) system provides localized pressure to heart valves through all heart phases; however, it does not stabilize the base of the heart.
It would instead be desirable to provide a system that permits localized pressure on selected regions of the heart (similar to the Mardill '363 device), but avoids its use of a solid silicone rubber band wrapped around the heart that may interfere with contraction and dilation.
It would also be advantageous to provide a system that provides localized pressure on the heart and also offers the advantages of a knit mesh jacket. Advantages of a knit mesh could include the fact that it allows for more freedom in heart contraction and dilation. In addition, a mesh band will advantageously self-attach to the heart by way of fibrotic encapsulation. This would assist in positioning the inflatable bladder(s) at a desired location and preventing unwanted movement of the bladder(s) in the future.